For example, Japanese Patent Application Laid-Open Publication No. 2005-93826 (Patent Document 1) describes a connection structure comprising: an electrode connection portion in which conduction is established by fusion bond between at least one of a first electrode provided in a first electric structure and a second electrode provided in a second electric structure and metal fine powder; and an intermediate connection portion in which conduction at an intermediate portion between the first electrode and the second electrode is established by conductive adhesive, wherein the metal fine powder is metal fine powder in which fusion bonding occurs at temperature equal to or lower than thermal hardening temperature of the conductive adhesive, and the conductive adhesive is a conductive adhesive including a conductive filler having a particle diameter in which fusion bonding does not occur at temperature equal to or lower than the thermal hardening temperature of the conductive adhesive.
And, Japanese Patent Application Laid-Open Publication No. 2005-340279 (Patent Document 2) describes a structure in which micro-particle conductive paste composed of a μm-size metal filler and nano-particle conductive paste composed of a nm-size metal filler is laminated and filled in layer form in a via-hole and the nano-particle conductive paste exists in layer form between the micro-particle conductive paste and a conductive layer.
And, in a technical paper, 11th Symposium on “Microjoining and Assembly Technology in Electronics”, pp 233 to 238, (2005. 2) (Non-Patent Document 1), review of application of nano-composite Ag paste material in which an Ag nano-particle is mixed with conventional Ag paste to die-bonding of a power semiconductor apparatus is reported. In this paper, there is a description that thermal cycling reliability, PCT (Pressure Cooker Test) reliability, a heat dissipation characteristic and an electrical conduction characteristic of a die-bonding portion are more excellent in the nano-composite Ag paste compared with conventional Ag paste connection. It is considered therein that the improvement of characteristic is achieved because the Ag nano-particle is interposed between Ag particles and causes a fusion bonding phenomenon by heating of 200° C., and therefore, the Ag nano-particle contributes to joint between the Ag particles. Note that, it is considered that, in order to improve the characteristic, a predetermined pressing pressure has to be applied in a processing of subjecting the nano-composite Ag paste to hardening baking.